/* 
 * C# port of Mozilla Character Set Detector
 * 
 * Original Mozilla License Block follows
 * 
 */

#region License Block
// Version: MPL 1.1/GPL 2.0/LGPL 2.1
//
// The contents of this file are subject to the Mozilla Public License Version
// 1.1 (the "License"); you may not use this file except in compliance with
// the License. You may obtain a copy of the License at
// http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
// for the specific language governing rights and limitations under the
// License.
//
// The Original Code is Mozilla Universal charset detector code.
//
// The Initial Developer of the Original Code is
// Netscape Communications Corporation.
// Portions created by the Initial Developer are Copyright (C) 2001
// the Initial Developer. All Rights Reserved.
//
// Contributor(s):
//
// Alternatively, the contents of this file may be used under the terms of
// either the GNU General Public License Version 2 or later (the "GPL"), or
// the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
// in which case the provisions of the GPL or the LGPL are applicable instead
// of those above. If you wish to allow use of your version of this file only
// under the terms of either the GPL or the LGPL, and not to allow others to
// use your version of this file under the terms of the MPL, indicate your
// decision by deleting the provisions above and replace them with the notice
// and other provisions required by the GPL or the LGPL. If you do not delete
// the provisions above, a recipient may use your version of this file under
// the terms of any one of the MPL, the GPL or the LGPL.
#endregion

using System;

namespace Mozilla.CharDet
{
    public enum SMState : int
    {
        Start = 0,
        Error = 1,
        ItsMe = 2,
    };

    public partial class SMModel
    {
        const int eStart = (int)SMState.Start;
        const int eError = (int)SMState.Error;
        const int eItsMe = (int)SMState.ItsMe;

        public PkgInt classTable;
        public int classFactor;
        public PkgInt stateTable;
        public int[] charLenTable;
        public string name;

        protected SMModel(PkgInt classTable, int classFactor, PkgInt stateTable, int[] charLenTable, string name)
        {
            this.classTable = classTable;
            this.classFactor = classFactor;
            this.stateTable = stateTable;
            this.charLenTable = charLenTable;
            this.name = name;
        }
    }

    public class CodingStateMachine
    {
        public CodingStateMachine(SMModel sm)
        {
            mCurrentState = SMState.Start;
            mModel = sm;
        }

        public SMState NextState(byte c)
        {
            //for each byte we get its class , if it is first byte, we also get byte length
            int byteCls = PkgInt.GETFROMPCK(c, mModel.classTable);

            if (mCurrentState == SMState.Start)
            {
                mCurrentBytePos = 0;
                mCurrentCharLen = mModel.charLenTable[byteCls];
            }
            //from byte's class and stateTable, we get its next state
            mCurrentState = (SMState)PkgInt.GETFROMPCK((int)mCurrentState * ((int)mModel.classFactor) + byteCls,
                                               mModel.stateTable);
            mCurrentBytePos++;
            return mCurrentState;
        }

        public void Reset() { mCurrentState = SMState.Start; }

        public int CurrentCharLen { get { return mCurrentCharLen; } }
        public string Name { get { return mModel.name; } }

        protected SMState mCurrentState;
        protected int mCurrentCharLen;
        protected int mCurrentBytePos;
        protected SMModel mModel;
    }
}
